Mac 49 carb issues
- Thread starter Johnnydarkgt350
- Start date
Jim - where are you located? My suggestion is go to a vintage go kart race in your area and there are a lot of "old guys" who know and still use that engine and could look it over in 5 minutes and tell you what needs to be changed. A year in a motor cycle shop tells me they didn't know shi_ about a McCulloch 49. Give me the state you are in and I will let you know where the closes event will be and when. By the way , how many teeth on the Hartman clutch. Are you using modern space chain or old #35 farm chain?
You are WAY up there in God's country. Not any vintage kart racing in your area. Might want to get on a site like https://www.vintagekartforum.com/ and get some suggestions. I know some good guys that work on that engine and it is not one of the favorites to rebuild because the top doesn't come off so if it did need to be re-bored it is a blind hole versus a through hole to work with. Sounds like yours only need to have the carb looked at by someone that knows what they are doing. The clutch on it is really a good reliable unit and because it is oil bath you don't have to worry about burning up shoes. You can get parts for the Hartman fairly easy from the vintage karting guys.
Back in the 50's, 60's and early 70's the #35 chain was not as wide as the space chain used today so the early clutches back then the distance between the sprocket and the drum was only .180. That gap is really important on what chain you use on a two speed mini-bike. It has to be old "farm chain" not the modern space chain that requires a gap of at least .200. Modern chain when you turn it on its side has an arc to it but old farm chain does not it stays straight as an arrow so your alignment is very critical when using the old farm chain. Space chain has forgiveness built into it. I am just saying when you use an old clutch be sure to use the old style chain because the modern chain my bind on you. I have put in new sprockets in some of the old Hartman clutches that used 9 or 10 tooth sprockets which made them adaptable to the modern chain. Just food for thought.
I use to buy 100' coils from Allied-Lock Industries in Dixon, IL but that has been quite a while back. I would think Farm & Fleet, Rural King, and Tractor Supply would all carry the less expensive chain. You don't go to a go kart shop that sells chain because that is all the modern "space chain" which is damn expensive compared to "farm chain". A 100' coil last last time I got it was less than 50 cents a foot. For some unknow reason everyone refers to #35 chain as roller chain and it is not. There are no rollers in the #35 chain, roller chain doesn't start until you get into the 1/2" pitch chain like #41, #420, #40 or #428. The first three are interchangeable when using a #41 sprocket. A #40 sprocket will only work with a #40 chain. #428 chain has a very large roller and will NOT fit any sprocket except a #428 sprocket.